After making her debut recording appearance on Junior M.A.F.I.A.'s Conspiracy album, Lil' Kim appeared on records by artists such as Mona Lisa, The Isley Brothers, and Total. With recording her debut album, Hard Core was mainly recorded at The Hit Factory in Manhattan, New York City.

Working with a number of producers, including Sean "Puff Daddy" Combs and Jermaine Dupri, the album featured edgy hardcore rap and explicit sexuality, as the title suggested, which at the time were two territories that had long been the province of male rappers.

The album was originally titled "Queen Bee".

Guest artists on the album included Jay-Z, The Notorious B.I.G., and other members of Junior M.A.F.I.A.

The promotional campaign for the album, including the album cover, featured provocative advertisements of Lil' Kim dressed up in a skimpy bikini, surrounded by furs.

During the recording sessions, Kim and B.I.G made a demo for the track "Street Dreams", never released officially.

The track “Big Momma Thang” was originally intended to be a diss towards Faith Evans and 2Pac but was re-recorded after Biggie disapproved of it.

The verse containing remarks against Faith was replaced by Jay-Z’s vocals while the third verse, which had a diss on 2Pac, was re-recorded by Lil' Kim.

"Hard Core" debuted and peaked at #11 on the US Billboard 200 and at #3 on the Billboard Top R&B/Hip-Hop Albums chart, selling 78,000 copies in its first week.

Despite not spending another week inside the top 30, the album was certified double platinum by the Recording Industry Association of America (RIAA) on March 14, 2001 and had sold 1,489,701 copies in the United States by November 2011.

In Canada, the album peaked at #62. As of November 2016, it had sold over five million copies worldwide.

Rolling Stone concluded in reviewing the album in the magazine's 2004 version of "The Rolling Stone Album Guide", wrote:

"Hip-hop had never seen anything like Brooklynite Kimberly Jones at the time of her solo debut: She single-handedly raised the bar for raunchy lyrics in hip-hop, making male rappers quiver with fear with lines like "You ain't lickin' this, you ain't stickin' this . . . I don't want d**k tonight/Eat my p***y right" ("Not Tonight"). Riding the wing of Notorious B.I.G.'s Ready to Die and Jay-Z's Reasonable Doubt, Kim's Hard Core helped put East Coast hip-hop back on top in the late '90s. The album's overreliance on old '70s funk samples doesn't detract a bit from the Queen Bee's fearless rhymes: In "Dreams", she demands service from R. Kelly, Babyface, and nearly every "R&B d**k" in the field. A landmark of bold, hilarious filth."

Jason Birchmeier of AllMusic wrote in his review of the album: "The relentless sexuality can be a bit much, even for the most ardent fans of hardcore rap. Even so, it's hard to think of such a categorically dirty rap album that's this accomplished, and it's furthermore refreshing to hear a woman turn the tables for once, particularly so cleverly with such a venerable supporting cast."